Just as the title says, I would like to know what personality you would replace Naruto's with. You can make it up, use a personality from another character in and out of the story itself or just use real people as a reference.

The two interesting ones to me are Light Yagami and Gandi:

With Light's personality Naruto's power would more noticeably go to his head. Unlike all generic shonen type main characters who never show any signs of corruption Naruto actually would. He would think of himself as God and strive to change the world to his ideals. He would actually be worse than the real Light since he would also think he is destined for success and a reincarnation of a god himself with many other people encouraging this.

With Gandi Naruto would truly be a preacher of peace. He would not fight with violence or encourage it in anyway. Unlike all types who end things with their first , he would end things with word. I like to think his words would be much more convincing than what Naruto usually comes up with. His plan of peace would also be much more organized. He and the people who believe in him would fight together to build a force that could not be ignored, unlike in the manga where all that agree with Naruto let him do all the work.